Could federal legislation have eased a key sticking point in the Air Canada dispute?

Flight attendants poised to strike this week have previously asked the federal government to address one of their biggest grievances — unpaid work.

The Canadian Union of Public Employees (CUPE) gave Air Canada a 72-hour strike notice early Wednesday. In response, the carrier issued a lockout notice starting at 1:30 a.m. ET on Saturday and says it will begin cancelling flights on Thursday.

CUPE represents more than 10,000 flight attendants who work for the major airline and its budget carrier Air Canada Rouge.

The two sides have been negotiating a new collective agreement since March, and the union says the most contentious issues at the bargaining table are wages — which it says haven't kept up with inflation — and unpaid work.

Flight attendants typically don't start getting paid until the plane is in motion and their compensation ends when the plane stops at the gate after landing — meaning they aren't paid for pre- and post-flight duties.

Air Canada has proposed paying flight attendants 50 per cent of their hourly wage for work done on the ground, but the union is asking for 100 per cent.

While it is a sticking point in the current labour dispute, flight attendants from a number of carriers have been calling on the federal government to make changes to the Canada Labour Code to address unpaid work.

WATCH | Flight attendants rally at airports across Canada:

Hundreds of Air Canada flight attendants are rallying at Vancouver international Airport... As a potential strike looms. Today's demonstration is part of a national day of action to protest low pay and unpaid work. Last week, Air Canada flight attendants voted overwhelmingly in favour of a strike mandate.

"It's not a huge ask, really. All people are asking for is to be paid for their time on the job," CUPE spokesperson Hugh Pouliot told CBC News.

"It's a very problematic situation, not just for Air Canada flight attendants, but flight attendants across the board."

Pouliot said flight attendants reached a "breaking point" due to ground delays experienced as Canadians slowly began flying again following the height of the COVID-19 pandemic.

Both the Conservatives and NDP introduced bills last parliamentary session that would have changed the Labour Code to ensure flight attendants are paid for pre- and post-flight duties. But both bills died when the House was prorogued earlier this year.

Pouliot said it's encouraging to see opposition parties supporting the changes, but said it's "tragic and confounding" that the Liberals haven't backed the move.

"I think you would be looking at a fundamentally different situation at Air Canada right now if the Liberals — a year and a half ago — had decided to play ball with the other parties," he said.

Wesley Lesosky, a flight attendant and president of CUPE's Air Canada component, told CBC News that he thinks the government ultimately needs to step in.

"We feel it should be addressed through the government and it shouldn't be used as bargaining capital at the table," Lesosky told host Sarah Galashan.

When asked by CBC News, a spokesperson from Jobs Minister Patty Hajdu's office didn't comment on whether the Liberals would support changes to the Labour Code to address flight attendants' concerns. But they encouraged Air Canada and CUPE to reach an agreement.

"During the bargaining process, parties establish agreements on wages, working conditions and other employment terms. Mediators will remain available until a deal is reached. The minister is closely monitoring this situation and encouraged both parties to stay at the table until a deal is found," the spokesperson said in an email.

Conservative Leader Pierre Poilievre and Conservative labour critic Kyle Seeback wrote a letter to Hajdu last week calling for the Liberals to make the Labour Code changes.

"No other federally regulated worker would accept being on the job without being paid and neither should flight attendants. It's time to end this outdated and unfair practice," their letter reads.

Speaking to reporters Wednesday, Conservative MP Michelle Rempel Garner reiterated her party's stance.

"As somebody who is a frequent flyer, I think they should be paid for [pre- and post-flight duties]," Rempel Garner told reporters on Parliament Hill.

"I hope that the union and management can come to an agreement on this, but certainly the principles that were contained in that bill last year are things we stand behind as a party."

The NDP announced Wednesday that it intends to reintroduce its own bill this fall.

"Every hour worked should be an hour paid," interim NDP Leader Don Davies said in a statement.

"The Liberals have done nothing to stop major airlines from exploiting their workers — most of whom are women. Instead, they handed those same airlines billions in taxpayer dollars. Workers deserve better."

Delta Air Lines is one of the only major North American airlines that offers ground pay to its flight attendants, paying them at half their hourly rate for 40 to 50 minutes of boarding time depending on the destination and aircraft.

Pouliot noted that Porter Airlines started paying flight attendants for some boarding duties this year while some smaller carriers — such as Pascan Aviation — pay full salary for ground duties.

But he cautioned that the issue of unpaid work could spill over into future labour negotiations with other Canadian airlines.

"If the government is interested in labour peace in the airline sector, then this is absolutely a priority," Pouliot said.

"To whatever extent it's resolved with Air Canada, it is going to be an issue for WestJet. It will be an issue for Flare. It will be an issue for Air Transat. It will be an issue for all of the air carriers in the country, because at every single one of these airlines flight attendants are beyond exhausted with working so many hours for free. It's going to stop one way or another."